Poa diaboli
Encyclopedia
Poa diaboli is a rare species of grass
known by the common name Diablo Canyon bluegrass. It is endemic to San Luis Obispo County, California
, where it is known from about five occurrences in the San Luis Mountains
near the coast. The type specimen was collected in Montaña de Oro State Park
and the grass was described as a new species in 2003. The grass occurs on rugged mountaintops and north-facing slopes in thin soils covering shale
rock within a few kilometers of the coastline. Its habitat includes chaparral
, oak woodland
, coastal sage scrub
, and Bishop pine forest
.
This species is a rhizomatous
or stolon
iferous perennial grass growing in mounds with stems up to half a meter tall. The inflorescence
is a panicle of flowers up to 10 centimeters long with upright or spreading branches. It flowers in March and April, the spikelets green with webby fibers.
This grass was found to exhibit "sequentially-adjusted gynomonoecism", a unique breeding system or intermediate between breeding systems. The species is dioecious
, with male and female flowers occurring on separate individuals, but there sometimes occur female plants that have some bisexual flowers, with working male and female parts, a syndrome called gynomonoecism. Whereas most plants that experience gynomonoecism have a fixed ratio of female and bisexual flowers throughout the season, this particular grass shifts its ratio, at times producing more bisexual flowers.
Threats to this rare species include the invasion of non-native grasses
, such as purple veldtgrass
(Ehrharta calycina).
Poaceae
The Poaceae is a large and nearly ubiquitous family of flowering plants. Members of this family are commonly called grasses, although the term "grass" is also applied to plants that are not in the Poaceae lineage, including the rushes and sedges...
known by the common name Diablo Canyon bluegrass. It is endemic to San Luis Obispo County, California
San Luis Obispo County, California
San Luis Obispo County is a county located along the Pacific Ocean in the Central Coast of the U.S. state of California, between Los Angeles and the San Francisco Bay Area. As of the 2010 census its population was 269,637, up from 246,681 at the 2000 census...
, where it is known from about five occurrences in the San Luis Mountains
Mount Buchon
Mount Buchon, also known as the San Luis Range, is a mountain range in San Luis Obispo County, California....
near the coast. The type specimen was collected in Montaña de Oro State Park
Montaña de Oro State Park
Montaña de Oro is a state park in California, United States. The park is located six miles southwest of Morro Bay and 2 miles south of Los Osos...
and the grass was described as a new species in 2003. The grass occurs on rugged mountaintops and north-facing slopes in thin soils covering shale
Shale
Shale is a fine-grained, clastic sedimentary rock composed of mud that is a mix of flakes of clay minerals and tiny fragments of other minerals, especially quartz and calcite. The ratio of clay to other minerals is variable. Shale is characterized by breaks along thin laminae or parallel layering...
rock within a few kilometers of the coastline. Its habitat includes chaparral
Chaparral
Chaparral is a shrubland or heathland plant community found primarily in the U.S. state of California and in the northern portion of the Baja California peninsula, Mexico...
, oak woodland
California oak woodland
California oak woodland is a plant community found throughout the California chaparral and woodlands ecoregion of California in the United States and northwestern Baja California in Mexico...
, coastal sage scrub
Coastal sage scrub
Coastal sage scrub is a low scrubland plant community found in the California chaparral and woodlands ecoregion of coastal California and northern Baja California. It is characterized by low-growing aromatic, and drought-deciduous shrubs adapted to the semi-arid Mediterranean climate of the...
, and Bishop pine forest
Bishop Pine
The Bishop Pine, Pinus muricata, is a pine with a very restricted range: mostly in the U.S. state of California, including several offshore Channel Islands, and a few locations in Baja California, Mexico...
.
This species is a rhizomatous
Rhizome
In botany and dendrology, a rhizome is a characteristically horizontal stem of a plant that is usually found underground, often sending out roots and shoots from its nodes...
or stolon
Stolon
In biology, stolons are horizontal connections between organisms. They may be part of the organism, or of its skeleton; typically, animal stolons are external skeletons.-In botany:...
iferous perennial grass growing in mounds with stems up to half a meter tall. The inflorescence
Inflorescence
An inflorescence is a group or cluster of flowers arranged on a stem that is composed of a main branch or a complicated arrangement of branches. Strictly, it is the part of the shoot of seed plants where flowers are formed and which is accordingly modified...
is a panicle of flowers up to 10 centimeters long with upright or spreading branches. It flowers in March and April, the spikelets green with webby fibers.
This grass was found to exhibit "sequentially-adjusted gynomonoecism", a unique breeding system or intermediate between breeding systems. The species is dioecious
Plant sexuality
Plant sexuality covers the wide variety of sexual reproduction systems found across the plant kingdom. This article describes morphological aspects of sexual reproduction of plants....
, with male and female flowers occurring on separate individuals, but there sometimes occur female plants that have some bisexual flowers, with working male and female parts, a syndrome called gynomonoecism. Whereas most plants that experience gynomonoecism have a fixed ratio of female and bisexual flowers throughout the season, this particular grass shifts its ratio, at times producing more bisexual flowers.
Threats to this rare species include the invasion of non-native grasses
Introduced species
An introduced species — or neozoon, alien, exotic, non-indigenous, or non-native species, or simply an introduction, is a species living outside its indigenous or native distributional range, and has arrived in an ecosystem or plant community by human activity, either deliberate or accidental...
, such as purple veldtgrass
Ehrharta calycina
Ehrharta calycina is a species of grass known by the common names perennial veldtgrass and purple veldtgrass. It is native to southern Africa, but it is known elsewhere as an introduced species, often becoming weedy...
(Ehrharta calycina).